The present invention relates generally to building constructions. More particularly, this invention relates to snap-fit assemblies for retaining greenhouse structural panels.
Present day greenhouses can be constructed with a number of different coverings. For example, greenhouses have been covered with thin, flexible plastic sheeting which is often available at low cost. This plastic sheeting is typically secured to the structural support members of the greenhouse. Various clip arrangements have been employed for this purpose. Many of these clips are constructed from aluminum. However, plastic sheeting often has to be replaced since it was easily damaged by wind, rain, and normal wear and tear.
As an alternative to plastic sheeting, plate glass can be used to cover the greenhouse. In order to connect glass to the structural support members of the greenhouse, a different type of fastening system is used. This fastening system needs to securely retain the relatively heavy panels but without breaking or cracking the glass.
Since glass panels break relatively easily, plastic panels have been employed instead. Presently, a number of different types of plastic structural panels are being used on greenhouses. One particular type of plastic panel is called polycarbonate structural sheeting and is sold by Polymark of Janesville, Wis. Polycarbonate sheets have several advantages over the glass structural panels. For example, while polycarbonate sheets can use similar fastening systems as glass sheets, polycarbonate sheets are less easily broken. Also, polycarbonate sheets can provide better insulating characteristics than glass sheets in many applications.
The present invention provides novel improvements to clip-type fastening systems used to connect greenhouse structural panels together. In the greenhouse industry, translucent structural panels, such as those of glass or polycarbonate, are connected to each other and also to the supporting structure or underlying framework of the greenhouse. Prior fastening or connecting clips have also been made from polycarbonate materials. One type of polycarbonate clip is called an H-Clip Profile and is available from Polymark of Janesville, Wis. The H-Clip Profile has been used for side wall and roof constructions in greenhouses. This device is a two-piece interlocking base and cap fastening system which can incorporate many of the desirable characteristics of polycarbonate sheeting. H-Clip Profile fastener systems are typically much lower in cost than comparable fastener systems formed from aluminum. Polycarbonate clips have better light transmission and thermal insulation characteristics than aluminum clips. Further, H-Clip Profiles have no exposed fasteners to the underlying framework. Their secure, interlocking grip can create a weather-tight seal without the use of neoprene gaskets. H-Clip Profiles have considerably less weight than metal fastener systems. Thus, shipping and construction costs are reduced and, at the same time, load stress on the greenhouse support structure is decreased. However, while the H-Clip Profile has a number of advantages over the prior fastener systems, it does not provide a uniform fastening system for structural panels having significantly different thicknesses. Also, this fastener system does not provide the same thermal insulating efficiencies as the structural panels it connects.
Another polycarbonate fastener is called an H-Profile. This is a single piece device and is also available from Polymark. H-Profiles include a plurality of opposing recesses for receiving the edges of structural panels. To install the panels, this clip is slid into position from one end of each panel. With H-Clip Profiles, on the other hand, the panels are set in place on the base and the cap is subsequently snap-fit into the base. However, both of these fastener devices support and retain the structural panels between substantially flat surfaces.
Various other panel fastener systems are known which are formed from materials other than polycarbonate. It has been known, for example, to provide a two-piece clip assembly with the separate members connected together by mating projections. These projections typically have a series of mutually interlocking teeth thereon to permit the separate members to be secured at selected distances to accommodate a particular panel thickness. However, without the use of additional clip assembly elements, these devices are not known to secure two panels together which each have a different thickness.
Other two-piece clip assemblies are known to have some flexibility in the cap member so as to bias the panels toward the base member. However, these typically secure the panels over a broad surface rather than at discrete points. Also, such devices often require compressible gaskets to provide proper sealing.
Therefore, it is an object of this invention to provide an improved fastening system.
It is another object of this invention to provide a fastening system that can accommodate a wide range of thicknesses of structural panels while using a uniform cap and a uniform base member.
A further object is to provide a fastening system that does not significantly restrict the transmission of light into the greenhouse.
Still another object is to provide a fastening system that has the same thermal characteristics as the structural panels being held.
Yet another object is to provide a fastening system with a base member that can be attached to a support purlin by various fasteners through the longitudinal center axis of the base member without effecting the fastening means of the system.
Yet still another object is to provide a clip arrangement that is self sealing to water and air.
A still further object is to provide a two-piece clip assembly for securing two panels each having a different thickness.
These and other objects of the present invention are attained by the provision of a fastener system having two mutually interlocking clip members, each clip member including a connection element and a pair of panel retaining walls. The connection element of one clip member is received and retained by the connection element of the other clip member through a series of interlocking hooks. The panel retaining walls of the cap clip member are flexibly arched and each includes a plurality of discrete panel engaging projections. The base clip member receives each panel on its retaining walls and can locate the panel ends against the connection element. The panel retaining walls of the cap clip member are independently flexible to permit each panel to have a different thickness. The discrete panel engaging projections are biased by the arch of the retaining walls to ensure proper sealing and secure panel retention.
The connection elements of the present invention are specially adapted to assist in retaining two panels, each having a different thickness. Each connection element includes spaced-apart arms having interlocking hooks formed thereon. Each hook arm of one connection element cooperates with a hook arm of the other connection element to act as a panel locking set. Within each such set at least one arm includes a plurality of spaced hooks such that different vertical spacing between clip members can be secured. Each locking set is operationally associated with the clip member retaining walls for a given panel and can be adjusted independently of the other locking set to establish different spacing for its retaining walls resulting in different thicknesses of panels being secured.
The components of the present invention are preferably formed from light transmitting materials, such as translucent polycarbonate. At the same time, additional barriers can be provided in the connection members to improve thermal insulation. Also, each set of spaced apart arms are spaced apart sufficiently to allow fasteners to be disposed within the connection member to secure the fastener system to the underlying support structure.
Other objects, advantages and novel features of the present invention will now become readily apparent upon consideration of the following description of preferred embodiments in conjunction with the drawings.